Copending application Ser. No. 08/789,841, now U.S. Pat. No. 5,777,397, filed Jan. 29, 1997, and application Ser. No. 08/734,959 filed Oct. 23, 1996, now U.S. Pat. No. 5,753,979, both assigned to the assignee of the present application, disclose a power supply having cables for supplying DC voltages to internal components of electronic systems such as a computer. These applications also disclose that the internal power supply includes sockets on the housing thereof for direct power supply to peripherals to the computer in the absence of connections to a house supply and the attending adapters. Similarly, copending application Ser. No. 08/994,908, filed Dec. 19, 1997 and also assigned to the assignee of the present application, discloses a power strip also includes sockets to provide a plurality of DC voltages. The use of such systems requires the user to know what voltage his peripheral requires and which socket is to be used. An incorrect connection could lead to damage to the peripheral.